spent hundreds if not thousands trying to stop it running hot ???
well i have the answer for you and it is fairly cheap , no need for multi pass alloy radiators or anything like that , although i do recommend that all cooling system componants be in good running order
this fix is for most if not all bypass type thermostats ie: looks like this ( specs will vary)
how the bypass thermostat works is ... that it will allow coolant to recirculate through the motor without having to go through the radiator as well as allowing coolant through the radiator
what i have found is that the bypass valve isnt blocking the flow of coolant that gets recirculated through the motor ( bypassing the radiator ) soon enough, basicly the thermostat has to open alot further before stopping this recirculation bypassing the radiator, this may mean the coolant temp has to reach around 100 deg or more before all the coolant has to go through the radiator
now the above pic shows some specs
54mm is the thermostat flange diameter
35mm is the closed thermostat hight between the flange and the bypass blocking plate
the 27.7 mm is the blocking plates diameter
now on my car the distance between where the thermostat flange sits and the surface where the bypass valve/ plate is to sit is 40mm , this means my thermostat would have to open 5mm before it will block the flow of coolant that bypasses the radiator, and in my case this means the coolant has to reach over 100 deg
what i have done is increased the closed thermostat hight between the flange and the bypass blocking plate to 38 mm , this means the thermostat now only has to open 2mm before all coolant has to travel through the radiator and the coolant temp is only around 90 deg at this stage
the results are impessive to me , i can tow my camper trailer up a mountain range with the temps maxing out at around 92 deg , i only have a falcon thermofan set up with the fans set to turn on at around 90 deg ( about 1/2 way on my factory guage) , and they easily kept up with cooling , hwy driving saw the temp guage sit around 1/3 and not needing the thermo fans at all to keep it cool
what i recommend to people who are having a hot running issue is to take some measurements to see how far your thermostat has to open before the blocking plate/ bypass valve makes contact with its intended seated surface, if it is 4mm or more then this mod is for you, reducing the closed thermostat gap to about 2mm should mean all the coolant will be traveling through your radiator by the time the coolant reaches about 90 deg, instead of recirculating hot coolant through the motor
this mod should allow coolant to recirculate and bypass the radiator when the motor is cold and force more coolant through the radiator once the motor is at running temp
any questions just ask away and i will try to answer them the best i can
Posted from the thread, So it is easy to find this data.
from what you have posted it looks like your thermostat is stuck wide open, and as you are not having any heating issues as yet i would just replace with a new thermostat, tridons TT228-180 is an 82 deg thermostat for the later model td42 and should work fine, or there is the high flow version TT2028-180 which is the same specs just high flow, both of these are just a strait put in and forget no mods needed.
the only uncertainty is how well the standard thermostat will cope under high load and/or heat situations, this is where (if your temps are fluctuating wildly) i recommend fitting a different thermostat or modding your standard thermostat so it can control the coolant temp better, now a factory thermostat which has the following specs
has to open up 9mm before closing the bypass hole so all the coolant flows through the radiator (ie: the 31mm distance in the diagram has to open up to 40mm to close the bypass hole), this is why alot of people have hot running issues with there TD42`s as the coolant temp has to rise about 20 deg before the bypass hole closes and the temp guage is all over the shop when the car looks at a hill.
the easiest thermostat to fit (no mods) is what i recommended to you first up "TT228-180 or TT2028-180" specs are
and is an improvement over the factory spec thermostat as they will control coolant temps a bit better because they only have to open 5mm before blocking the bypass hole, (the bypass hole is 40mm below the flange of the thermostat) , but even this thermostat allows the coolant temps to fluctuate a bit although not as bad as the factory thermostat
this is where i got a different thermostat again (couldnt find one with the specs i wanted so i had to get one and moddify it) the only one i could find close enough to suit my needs with minimal mods needed was a dayco DT79H which has the following specs
now this thermostat has a 41mm distance from the flange to the bypass blocking plate, if i fitted it strait in it would mean the bypass hole is always blocked which is not what you want, you need to change the 41mm distance to about 37-38mm so when the motor is cold the coolant will still circulate through the motor, basicly you need to space the bypass blocking plate up about 3 to 4mm
the DT79a rated at 82deg
http://www.eziautoparts.com.au/dayco-thermostat-dt79a.html
the DT79h rated at 85deg
http://www.eziautoparts.com.au/dayco-thermostat-dt79h.html
the DT80g rated at 89deg
http://www.eziautoparts.com.au/dayco-thermostat-dt80g.html
the other option is to weld in an alloy washer/ring on top of the bypass hole to reduce the distance the thermostat has to open before blocking the bypass hole, this way you could still use the factory thermostat and have better control of the coolant
well i have the answer for you and it is fairly cheap , no need for multi pass alloy radiators or anything like that , although i do recommend that all cooling system componants be in good running order
this fix is for most if not all bypass type thermostats ie: looks like this ( specs will vary)
how the bypass thermostat works is ... that it will allow coolant to recirculate through the motor without having to go through the radiator as well as allowing coolant through the radiator
what i have found is that the bypass valve isnt blocking the flow of coolant that gets recirculated through the motor ( bypassing the radiator ) soon enough, basicly the thermostat has to open alot further before stopping this recirculation bypassing the radiator, this may mean the coolant temp has to reach around 100 deg or more before all the coolant has to go through the radiator
now the above pic shows some specs
54mm is the thermostat flange diameter
35mm is the closed thermostat hight between the flange and the bypass blocking plate
the 27.7 mm is the blocking plates diameter
now on my car the distance between where the thermostat flange sits and the surface where the bypass valve/ plate is to sit is 40mm , this means my thermostat would have to open 5mm before it will block the flow of coolant that bypasses the radiator, and in my case this means the coolant has to reach over 100 deg
what i have done is increased the closed thermostat hight between the flange and the bypass blocking plate to 38 mm , this means the thermostat now only has to open 2mm before all coolant has to travel through the radiator and the coolant temp is only around 90 deg at this stage
the results are impessive to me , i can tow my camper trailer up a mountain range with the temps maxing out at around 92 deg , i only have a falcon thermofan set up with the fans set to turn on at around 90 deg ( about 1/2 way on my factory guage) , and they easily kept up with cooling , hwy driving saw the temp guage sit around 1/3 and not needing the thermo fans at all to keep it cool
what i recommend to people who are having a hot running issue is to take some measurements to see how far your thermostat has to open before the blocking plate/ bypass valve makes contact with its intended seated surface, if it is 4mm or more then this mod is for you, reducing the closed thermostat gap to about 2mm should mean all the coolant will be traveling through your radiator by the time the coolant reaches about 90 deg, instead of recirculating hot coolant through the motor
this mod should allow coolant to recirculate and bypass the radiator when the motor is cold and force more coolant through the radiator once the motor is at running temp
any questions just ask away and i will try to answer them the best i can
Posted from the thread, So it is easy to find this data.
from what you have posted it looks like your thermostat is stuck wide open, and as you are not having any heating issues as yet i would just replace with a new thermostat, tridons TT228-180 is an 82 deg thermostat for the later model td42 and should work fine, or there is the high flow version TT2028-180 which is the same specs just high flow, both of these are just a strait put in and forget no mods needed.
the only uncertainty is how well the standard thermostat will cope under high load and/or heat situations, this is where (if your temps are fluctuating wildly) i recommend fitting a different thermostat or modding your standard thermostat so it can control the coolant temp better, now a factory thermostat which has the following specs
has to open up 9mm before closing the bypass hole so all the coolant flows through the radiator (ie: the 31mm distance in the diagram has to open up to 40mm to close the bypass hole), this is why alot of people have hot running issues with there TD42`s as the coolant temp has to rise about 20 deg before the bypass hole closes and the temp guage is all over the shop when the car looks at a hill.
the easiest thermostat to fit (no mods) is what i recommended to you first up "TT228-180 or TT2028-180" specs are
and is an improvement over the factory spec thermostat as they will control coolant temps a bit better because they only have to open 5mm before blocking the bypass hole, (the bypass hole is 40mm below the flange of the thermostat) , but even this thermostat allows the coolant temps to fluctuate a bit although not as bad as the factory thermostat
this is where i got a different thermostat again (couldnt find one with the specs i wanted so i had to get one and moddify it) the only one i could find close enough to suit my needs with minimal mods needed was a dayco DT79H which has the following specs
now this thermostat has a 41mm distance from the flange to the bypass blocking plate, if i fitted it strait in it would mean the bypass hole is always blocked which is not what you want, you need to change the 41mm distance to about 37-38mm so when the motor is cold the coolant will still circulate through the motor, basicly you need to space the bypass blocking plate up about 3 to 4mm
the DT79a rated at 82deg
http://www.eziautoparts.com.au/dayco-thermostat-dt79a.html
the DT79h rated at 85deg
http://www.eziautoparts.com.au/dayco-thermostat-dt79h.html
the DT80g rated at 89deg
http://www.eziautoparts.com.au/dayco-thermostat-dt80g.html
the other option is to weld in an alloy washer/ring on top of the bypass hole to reduce the distance the thermostat has to open before blocking the bypass hole, this way you could still use the factory thermostat and have better control of the coolant